<?php

namespace console\controllers;

use yii\console\Controller;
use yii\helpers\ArrayHelper;
use yii\helpers\Html;

class DemoController extends Controller {



    function actionIndex() {

        $a = [
            'a' => [
                'b' =>  [
                    'c' => 5
                ]
            ]
        ];
        $d = ArrayHelper::keyExists('a', $a);
        var_dump($d);
    }
}